Field of the Invention
The invention relates to an integrated semiconductor circuit.
As is known, integrated semiconductor circuits have what are referred to as pads, which are contact-connected to terminal pins of a housing and through which input or output signals to be processed by the semiconductor circuit are fed in or out or to which a supply potential is applied. The pads for signal input and output, in particular, are subjected to the requirement that adaptation to the connected line be performed.
By way of example, semiconductor circuits having the same circuit layout are to be connected to different bus systems. In that case, through the use of suitable circuit measures, the input/output parameters of the connections can be adapted to the desired value by suitable capacitance and resistance circuitry. If, on one hand, corresponding components outside the integrated semiconductor circuit are used for that purpose, that leads to a higher outlay for the circuit board construction and to corresponding disadvantages, e.g. an increased risk of failure. If, on the other hand, such components are realized in an integrated manner using conventional measures on the semiconductor chip, the area requirement of the circuit is increased, particularly by the realization of capacitances. A large number of process steps extending down into deeper layers of the integrated circuit are necessary in order to fabricate the integrated capacitor. Therefore, the integrated realization furthermore necessitates additional development outlay and a multiplicity of exposure masks separately assigned to each adaptation variant.
European Patent Application 0 409 256 A2 describes an integrated semiconductor circuit in which dummy structures are used to stabilize an internal supply voltage or to set a delay time for an internal signal. To that end, metal lines of the dummy structure which are not required for other purposes are connected to a supply potential line or to a signal output of a circuit block. The length of the signal line is trimmed through the use of a laser beam in order to provide the desired capacitance.